LED optical system with multiple levels of secondary optics

Abstract

An optical system for lighting fixtures uses light emitting diodes arranged in a 2-D array. In one embodiment, a lighting system comprises a framework carrying a plurality of diodes, where each diode has an associated optic that projects the light with a “high,”“medium” or “low” vertical throw, as provided by prismatic “teeth” that refract and reflect light rays in a predetermined manner so that the combined illumination patterns of each diode can blend to generally uniformly illuminate a target surface without dark spots or regions. Each optic has a common primary portion and a selected secondary portion whose tooth / teeth have a “swept” geometry for better angular (vertical and / or horizontal) control of light rays. Structural variations between different secondary portions reside in various factors, including plurality of teeth, length of the tooth along the longitudinal axis A, curvature(s) in the vertical and / or horizontal directions, and angularity or tightness of curvature of the swept geometry.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Patent Application No. 61 / 234,248, Aug. 14, 2009, the entire disclosure of which is hereby incorporated by reference.FIELD OF INVENTION[0002]The present invention relates to lighting systems, in particular lighting systems using light emitting diodes to illuminate a target surface.BACKGROUND OF INVENTION[0003]A luminaire or light fixture includes at least a light source (or lamp), electrical components and a housing. A standard luminaire for illumination of surfaces, areas or objects typically uses a single light source and may include an optical arrangement to control raw light output from the single light source for more efficient distribution of the light. The optical arrangement can be a lens, a refractor, a reflector, or a combination of these optical elements that controls the light and produces a desired illumination pattern or distribution.[0004]Most standard lamps come in ve...

AI Technical Summary

Benefits of technology

The system achieves a high degree of uniformity and efficiency in light distribution, minimizing waste and exceeding the light output of standard lamp sources by directing light more effectively over larger areas, with the ability to create unique illumination patterns tailored for specific applications.

Problems solved by technology

Previously, these devices were not sufficiently efficacious compared to a standard light source such as fluorescent, high intensity discharge, or incandescent.

However, LEDs produce a Lambertian distribution which only emanates from the front of the diodes and is not uniform in all directions.

As such, most LEDs have a built-in lens to control the raw light output in a primary fashion, but a primary lens or optic has not proven to provide the necessary optical control to provide illumination patterns that are suitable to replace standard luminaire optical systems and lamp sources.

Problems with direct replacement of standard lamp sources stem from the inability to mimic the emanation of the standard sources raw light output.

Thus, standard optical systems are often useless for LED systems as they are designed around a point source, linear source, or small area source.

These types of LED systems have not yet proven to exceed the light distributions of standard lamp sources.

Typically, their distributions fall short or they have similar amounts of waste light due to only having one level of control used over the LED array.

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